Original GT500 Spark Plugs

[propayne]

One of my favorite vintage performance logos -

- Phillip

[shelbydoug]

If you are using period NOS  Autolites, you might be just fine, but as much as it pains me to admit this, being a Ford die-hard, modern Autolite plugs just aren't the same as they used to be.

Same can be said for Champion.....and Goodyear tires.

For anything actually being used, and that includes my nearly 900 horse big blocks, I now use nothing but NGK.  😳  Blasphemy, I know.

Interesting observation! Here's my experience. I have NGK's in my Pantera. Their heat range is expanded and is in between a 32 and a 42.

The most accurate plugs made now conforming to the original heat ranges of plugs, you're gonna hate me, get ready...are Champions. They are the only ones that have the originial heat ranges.

I use them to determine the best plug to run, then switch them to the NGK's. I have those in my 68 GT350 w/347 and AFR heads.

I'm very impressed with their quaility BUT f9y's are right on it. Sorry!

[2112]

Can they work? Sure, if I am willing to chase down failing plugs and swap them out hoping the replacement will continue to function as promised.

If I want to put in 8 plugs and have them work right out of the boxes, for the effective life span of the plugs, I use NGK.  I just don't like  fighting defective plugs if I don't have to. And these are in boat engines with all the access in the world (albeit 16 plugs).

#7 & #8 in an FE in a Mustang? I would rather do it once & put in plugs that I can count on.

Just my 2 cents.

[1967 eight barrel]

Doug:
I wish I had a dollar for every champion plug that was replaced under warranty when I worked for Chrysler as the Wholesale Export parts director for about six months waiting for my slot at the academy.  Why they chose to use them I'll never know, but the crazy failures I saw I have never seen with another manufacturer. It must have cost Chrysler/Jeep millions of dollars in labor.
I steer clear of Champion plugs. I'd rather have ran AC plugs than Champions!

[shelbydoug]

I didn't speak of their quality, just of their temperature range accuracy in the Fords. I'm not saying that you are wrong and I am right. I'm just sharing my experiences in that others may use it to find their own path.

When I actually relied on them, the main issue I had was that they had accelerated tip wear.

I do not have any experience with the original Autolite 's but do with the Motorcrafts and some with the AC's.



To me, the Motorcraft and the AC's are the same plug and I originally had issues all along compounded with weak stock ignition systems.
Then, all I could do was deal with it wrongly as a plug temperature range issue. Now I know better.

That just manifested itself when I started with Webers in about '78. That needed to be resolved and now is. Once the spark strength was there, the temperature ranges of the Motorcrafts became effective for me and the 32's worked and became the plug of choice.

If you run a stock ignition system, issues will/could emerge and look like the plugs.



It is important to acknowledge that there are multiple factors running concurrently here and it isn't just the plugs. For instance, if you change the cam from stock, that's another factor.




A BF42 is an adequate solution, albeit a factory band-aid but don't blame plugs for other issues/considerations. It actually is not simple and gets complicated including what spark plug wires you are using.

Remember the factory's concern over 7-8 cross fire? 

[Blackcar]

What year did the autolite BF 32's come out with the GT 40 on the box ?

[1967 eight barrel]

The red and black Motorcraft with the GT 40 box is 70's.

[Blackcar]

Autolite and the GT40 logo

[s2ms]

Saw this used set of star logo BF-42's this morning if anyone is interested. Not mine, just passing it on...

https://www.ebay.com/itm//362625080270